diff options
Diffstat (limited to 'Lib/test/test_collections.py')
| -rw-r--r-- | Lib/test/test_collections.py | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py index 13ae9bf..ddf8398 100644 --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -2,6 +2,8 @@ import unittest, doctest from test import test_support from collections import namedtuple, Counter, Mapping import pickle, cPickle, copy +from random import randrange +import operator from collections import Hashable, Iterable, Iterator from collections import Sized, Container, Callable from collections import Set, MutableSet @@ -350,6 +352,8 @@ class TestCounter(unittest.TestCase): def test_basics(self): c = Counter('abcaba') + self.assertEqual(c, Counter({'a':3 , 'b': 2, 'c': 1})) + self.assertEqual(c, Counter(a=3, b=2, c=1)) self.assert_(isinstance(c, dict)) self.assert_(isinstance(c, Mapping)) self.assert_(issubclass(Counter, dict)) @@ -379,6 +383,7 @@ class TestCounter(unittest.TestCase): c['a'] += 1 # increment an existing value c['b'] -= 2 # sub existing value to zero del c['c'] # remove an entry + del c['c'] # make sure that del doesn't raise KeyError c['d'] -= 2 # sub from a missing value c['e'] = -5 # directly assign a missing value c['f'] += 4 # add to a missing value @@ -394,7 +399,8 @@ class TestCounter(unittest.TestCase): self.assertEqual(repr(c), 'Counter()') self.assertRaises(NotImplementedError, Counter.fromkeys, 'abc') self.assertRaises(TypeError, hash, c) - c.update(dict(a=5, b=3, c=1)) + c.update(dict(a=5, b=3)) + c.update(c=1) c.update(Counter('a' * 50 + 'b' * 30)) c.update() # test case with no args c.__init__('a' * 500 + 'b' * 300) @@ -442,6 +448,43 @@ class TestCounter(unittest.TestCase): self.assertEqual(dict(Counter(s)), dict(Counter(s).items())) self.assertEqual(set(Counter(s)), set(s)) + def test_multiset_operations(self): + # Verify that adding a zero counter will strip zeros and negatives + c = Counter(a=10, b=-2, c=0) + Counter() + self.assertEqual(dict(c), dict(a=10)) + + elements = 'abcd' + for i in range(1000): + # test random pairs of multisets + p = Counter(dict((elem, randrange(-2,4)) for elem in elements)) + q = Counter(dict((elem, randrange(-2,4)) for elem in elements)) + for counterop, numberop, defneg in [ + (Counter.__add__, lambda x, y: x+y if x+y>0 else 0, True), + (Counter.__sub__, lambda x, y: x-y if x-y>0 else 0, False), + (Counter.__or__, max, False), + (Counter.__and__, min, False), + ]: + result = counterop(p, q) + for x in elements: + # all except __add__ are undefined for negative inputs + if defneg or (p[x] >= 0 and q[x] >= 0): + self.assertEqual(numberop(p[x], q[x]), result[x]) + # verify that results exclude non-positive counts + self.assert_(x>0 for x in result.values()) + + elements = 'abcdef' + for i in range(100): + # verify that random multisets with no repeats are exactly like sets + p = Counter(dict((elem, randrange(0, 2)) for elem in elements)) + q = Counter(dict((elem, randrange(0, 2)) for elem in elements)) + for counterop, setop in [ + (Counter.__sub__, set.__sub__), + (Counter.__or__, set.__or__), + (Counter.__and__, set.__and__), + ]: + counter_result = counterop(p, q) + set_result = setop(set(p.elements()), set(q.elements())) + self.assertEqual(counter_result, dict.fromkeys(set_result, 1)) import doctest, collections |